Prior art aerial lifts or hydraulic platforms are of many types. In U.S. Pat. No. 4,453,672, there is disclosed an aerial lift which permits rotation about a vertical axis during use through a full 360.degree. to any position. The lift accommodates extensions and retractions of an extensible boom formed as a part of conventional lower and upper booms. A single hydraulic cylinder raises and lowers a pair of pivotally connected lower and upper booms. The upper and lower booms are connected together such that the movement of the lower boom causes the outward end of the upper boom to move generally vertically upwardly rather than in an arc toward or away from the vehicle. A fluid supply line for a nozzle at the upper end of the lift accommodates relative movement between various parts of the lift as well as rotation of the lift to different angular positions.
One of the problems associated with the aerial lift disclosed in U.S. Pat. No. 4,453,672 is that the upper boom with the fluid nozzle at the end thereof can move only from the horizontal upwardly. It can not be tilted upwards so that the boom can be extended downwardly toward the ground. Further, the nozzle on the end of the boom can be moved in a vertical plane but it can not be directed in a horizontal plane. Thus, it is difficult to use such aerial lift for purposes such as fighting fires because the vehicle itself must be positioned in certain instances to direct the fluid flow and in other instances can not project the fluid from positions near the ground level. Further, the entire boom assembly must be rotated to aim the fluid in various directions.
It would be advantageous to have an aerial lift assembly which has an upper boom that could be tilted toward the ground as well as pivoted upwardly. It would also be advantageous to have a nozzle assembly on the outer end of the upper boom which not only could be pivoted in the vertical plane but could also be rotated in a plane perpendicular to the vertical plane.
Further, where a fire is contained within the structure, it would be advantageous to know where the fire needs control most urgently. If the hot spots were known, the fire could be attacked at those points.
Also, in remotely controlled aerial lifts, the fluid flow quantity is fixed and can be adjusted only by changing the pressure.
In addition, where the operator is sitting in a vehicle, it is sometimes difficult to have a complete view of the object containing the fire because of other objects blocking the view.
Finally, if the structure or object containing the fire is surrounded with a great deal of smoke, it is difficult to know how close the nozzle assembly of the aerial lift is to the structure containing the fire because of the smoke.
The present invention adds a piercing nozzle to the boom which has a hardened steel point and a sprayer unit that enables the piercing nozzle to be forced through the wall of the structure containing the fire so that the flame-retardant fluids may be injected directly into the interior of the structure. In addition, a heat sensor is mounted on the end of the boom assembly, so that it can be used to scan the object containing the fire and determine where the hot spots are located. The piercing nozzle can then be directed towards the hot spots and pierce the structure so that the fire retardant fluids can be injected into the interior of the container at the proper locations.
While the most efficient means of forcing the piercing nozzle through the wall of a structure is to align the upper boom perpendicular to the penetration point with the piercing nozzle parallel with and in axial alignment with the boom, the piercing nozzle may hit an obstruction that is difficult to pierce. It may tend to force the piercing nozzle to form an angle with the boom which will then create side forces perpendicular to the longitudinal axis of the piercing nozzle and if force is continued to be applied, damage may occur to the piercing nozzle, the mount on which it is positioned or the drive means that is tending to resist the side movement of the forces on the piercing nozzle. Therefore, a slip clutch is mounted between the outer end of the boom and the drive means such that the undesirable side forces on the elongated piercing nozzle are limited to a predetermined value in the Y plane perpendicular to the piercing direction of the elongated nozzle. This will protect the piercing nozzle, the mounting apparatus and the drive means from damages.
Also, because the structure containing the fire may be surrounded with thick smoke so that the operator cannot see the container, an acoustic proximity system is placed on the end of the boom to detect the position of the end of the boom relative to the structure as it is approaching the structure, even though the structure cannot be seen.
Further, a video camera is mounted on the outer end of the boom so that the operator can raise the boom and the aerial lift high above the structure containing the fire and can scan the area about the structure so that the picture can be transmitted back to the operator in the cab of the vehicle thereby ensuring that all information necessary to the containment of the fire can be available to the operator.
Finally, the present invention overcomes the disadvantages of the prior art by having a remote electronic control of the fluid flow quantity by restricting an orifice and simultaneously controlling the flow pattern by varying the orifice fluid flow direction. This control is accomplished by switches in the cab that can be mounted as needed.
The present invention also allows the upper boom to be tipped upwardly approximately 45.degree. above horizontal and to be tilted downwardly to a point just above the cab of the vehicle. In this position, extension of the upper boom will position the nozzle device in various positions below the horizontal plane to address a variety of tasks. By extending the boom, the nozzle can be lowered to ground level or below ground level if necessary to reach over embankments, bridges or piers. The nozzle itself has the capability of rotating 90.degree. either side of the center line of the boom. This allows the nozzle to be rotated 180.degree. in the horizontal plane. In addition, the nozzle can be rotated plus 45.degree. above the center line of the boom and minus 180.degree. below the center line of the boom for a total rotation in the vertical plane of 225.degree.. This unique feature makes positioning of the vehicle less critical in respect to a fire.
Thus, it is an important aspect of the present invention to provide a movable boom which can be elevated not only above the horizontal but can also be tipped downwardly below the horizontal and extended to the point that a nozzle on the outer end thereof can be lowered to or below ground level.
It is also an important aspect to the present invention to have a nozzle that can operate in both the horizontal plane and vertical plane with respect to the center line of the boom thereby enabling the nozzle to be extended into a doorway, for example, of a building or a vehicle and the nozzle rotated in both horizontal and vertical planes to extinguish a fire on the inside of the object.